I have little experience with mopar. But it sounds like If it were me I would build your 318 and spray it. Like you said its only a Sunday driver and no drag racing. God help you if you get caught street racing in East Tn. A girl just got killed by a street racer here. And there just salivating to catch anyone doing it. I know thats of topic a little, but why build a 450 hp car if your not gonna race it some .